1.4-6 GHz erbium doped fiber laser using rational harmonic mode-locking technique

By means of the technique of rational harmonic mode-locking(RHML), we succe eded in obtaining the optical pulses at repetition rate (f(p)) being intege r multiples of the RF drive frequency(f(m) approximate to 1.4 GHz) with det uning ratio of > 10(-6). The generation of maximum frequency was about 6 GH z and the stable rational harmonic mode-locking occurs only at f(P) = 2f(m) . According to the result of our experiments, we put forth a possible mecha nism of using RHML to generate high bit-tate pulses and point out the cause of the occurrence of instability in higher RHML. Furthermore, we demonstra te an effective method to elliminate the amplitude fluctuations of output p ulse train.